core: names are the device's, so drop the per-profile account

A name's profile is the record it resolves to, not the key that owns it, so
the account level was carrying a mapping nothing needs. It was also the only
source of the profile to account ambiguity after a restore, of /_wallet
bind, and of the index gap and the refusal that told a visible profile an
account was held by one it cannot see. All of it goes.

Names sit in account 0 from index 1. Index 0 is left unused so neither the
names nor the profile accounts, which start at 1, claim the origin of both
dimensions. users gains no columns at all now, so the migration is one
CREATE TABLE.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Rvc3HbiWBTqbAvRT45G5oX

src/Simplex/Chat/Store/Postgres/Migrations/chat_schema.sql

@@ -1517,9 +1517,7 @@ CREATE TABLE test_chat_schema.users (
     auto_accept_member_contacts smallint DEFAULT 0 NOT NULL,
     is_user_chat_relay smallint DEFAULT 0 NOT NULL,
     client_service smallint DEFAULT 0 NOT NULL,
-    auto_accept_group_invitations smallint DEFAULT 0 NOT NULL,
-    wallet_seed_id bigint,
-    wallet_account_index bigint
+    auto_accept_group_invitations smallint DEFAULT 0 NOT NULL
 );
 
 
@@ -1538,7 +1536,7 @@ ALTER TABLE test_chat_schema.users ALTER COLUMN user_id ADD GENERATED ALWAYS AS
 CREATE TABLE test_chat_schema.wallet_seeds (
     wallet_seed_id bigint NOT NULL,
     seed bytea NOT NULL,
-    next_account_index bigint DEFAULT 0 NOT NULL,
+    next_name_index bigint DEFAULT 1 NOT NULL,
     single_seed smallint DEFAULT 1 NOT NULL
 );
 
@@ -2667,10 +2665,6 @@ CREATE UNIQUE INDEX idx_user_contact_links_group_id ON test_chat_schema.user_con
 
 
 
-CREATE INDEX idx_users_wallet_seed_id ON test_chat_schema.users USING btree (wallet_seed_id);
-
-
-
 CREATE UNIQUE INDEX idx_wallet_seeds_single_seed ON test_chat_schema.wallet_seeds USING btree (single_seed);
 
 
@@ -3350,11 +3344,6 @@ ALTER TABLE ONLY test_chat_schema.user_contact_links
 
 
 
-ALTER TABLE ONLY test_chat_schema.users
-    ADD CONSTRAINT users_wallet_seed_id_fkey FOREIGN KEY (wallet_seed_id) REFERENCES test_chat_schema.wallet_seeds(wallet_seed_id) ON DELETE RESTRICT;
-
-
-
 ALTER TABLE ONLY test_chat_schema.xftp_file_descriptions
     ADD CONSTRAINT xftp_file_descriptions_user_id_fkey FOREIGN KEY (user_id) REFERENCES test_chat_schema.users(user_id) ON DELETE CASCADE;